Lubricating Oil Composition Having Improved Air Release

ABSTRACT

The invention provides a lubricating oil composition comprising a ethylene/α-olefin copolymer and, optionally, and additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester. The invention also provides a method of improving air release of a lubricating oil composition by mixing an ethylene/α-olefin copolymer with an oil of lubricating viscosity.

FIELD OF INVENTION

The present invention relates to a lubricating oil composition which has improved air release properties. The invention also provides a method of improving air release of a functional fluid, such as a lubricating oil.

BACKGROUND OF THE INVENTION

In order to reduce the friction and wear of moving parts, lubricants must have sufficient viscosity at the normal operating temperature of the moving parts. When lubricating films are too thin, parts are not adequately protected leading to reduced operable lifespan. Further, low viscosity at maximum operating temperatures can cause equipment to seize or wear unacceptably. Sufficient viscosity is also necessary to protect hydraulic pumps and keep them operating efficiently by preventing leakage or internal pump recycling.

Air release properties of functional fluids or lubricants affect the maximum fluid viscosity of the lubricant. As functional fluids or lubricants move through a system or moving parts, air becomes trapped in the fluid. Often systems are designed with additional fluid reservoirs to allow functional fluids or lubricants to rest and release trapped air. Sometimes the inclusions of these reservoirs are impractical due to sizing constraints for the equipment or the amount of additional fluid or lubricant necessary to keep the system operating continuously.

In general, for thicker (higher viscosity) functional fluids, air bubbles are released more slowly from the fluid. If the amount of air trapped in the fluid is too high, the fluid may not form a complete film in required contact zones of equipment or may not be able to sufficiently maintain system pressure. Compression of air bubbles in a fluid may lead to ignition of the vapor inside the bubble, also known as the micro-diesel effect. These micro explosions accelerate fluid degradation and lead to structural damage of metal parts. Other issues caused by trapped air include cavitation, erosion, and high noise levels.

Certain fluid and lubricant additives are known to negatively impact air release from the fluid. Typically, air release is improved by reducing the viscosity of the fluid. It would be desirable to have an additive that can improve the air release of a functional fluid while maintaining desired viscosity grades.

SUMMARY OF THE INVENTION

One objective of the present invention is to improve the air release of a functional fluid or lubricating oil by mixing a base oil with an ethylene/α-olefin copolymer. Another objective of the present invention is to provide a lubricating composition having a desired lubricating viscosity with improved air release over the base oil alone.

In one embodiment of the invention, the objectives are achieved by a lubricating oil composition which comprises (a) a base oil of lubricating viscosity; and (b) an ethylene/α-olefin copolymer. In another embodiment, a lubricating oil composition of the present invention comprises (a) a base oil of lubricating viscosity, (b) an ethylene/α-olefin copolymer composition, and (c) an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester.

In one embodiment of the invention, the objectives are achieved by a lubricating oil composition which comprises (a) a base oil of lubricating viscosity; and (b) an ethylene/α-olefin copolymer. In another embodiment, a lubricating oil composition of the present invention comprises (a) a base oil of lubricating viscosity, (b) an ethylene/α-olefin copolymer composition, and (c) an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester wherein the additive is obtained by reacting a phosphorous sulfide with one or more alcohols having about 3 to about 13 carbon atoms to form a thiophosphoric acid ester, further reacting the thiophosphoric acid ester with an alkylene oxide to form a hydroxyl-substituted ester of thiophosphoric acid, and further reacting said hydroxyl-substituted ester of thiophosphoric acid with a phosphorous oxide to form a an acidic phosphoric acid intermediate, and salting said acidic phosphoric acid intermediate with one or more amines wherein said amines contain one or more hydrocarbyl groups having from 2 to 30 carbon atoms.

In another embodiment, a lubricating oil composition of the present invention comprises (a) a base oil of lubricating viscosity, (b) 2% to 17% by weight of an ethylene/α-olefin copolymer composition, and (c) 0.04% to 0.20% of (c) an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester.

The present invention also provides a method of improving the air release of a functional fluid, such as a lubricating oil, the method comprising (i) providing (a) a base oil of lubricating viscosity and (b) an ethylene/α-olefin copolymer; (ii) mixing the base oil of lubricating viscosity with the ethylene/α-olefin copolymer to obtain a functional fluid.

In another embodiment, the present invention also provides a method of improving the air release of a functional fluid, such as a lubricating oil, the method comprising (i) providing (a) a base oil of lubricating viscosity, (b) providing an ethylene/α-olefin copolymer, and (c) providing an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester and (ii) mixing (a), (b), and (c) to obtain a functional fluid.

In another embodiment, the present invention also provides a method of improving the air release of a functional fluid, such as a lubricating oil, the method comprising (i) providing (a) a base oil of lubricating viscosity, (b) providing an ethylene/α-olefin copolymer, and (c) providing an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester and (ii) mixing (a), (b), and (c) to obtain a functional fluid, wherein said functional fluid comprises 2% to 17% by weight of the ethylene/α-olefin copolymer and 0.04% to 0.20% by weight of the additive comprising the reaction product of a hydroxy-substituted triester of a phosphorothioic acid with an inorganic phosphorus reagent selected from the class consisting of phosphorous acids, phosphorus oxides, and phosphorus halides and neutralizing a substantial portion of said acidic intermediate with an amine.

In one embodiment, the invention provides a method of lubricating an industrial gear comprising supplying to the industrial gear a lubricant composition as disclosed herein. In another embodiment, the invention provides a method of improving air release in an industrial gear lubricating oil.

As used herein, the transitional term “comprising”, which is synonymous with “including”, “containing”, or “characterized by”, is inclusive or open-ended and does not exclude additional, un-recited elements or method steps. However, in each recitation of “comprising” herein, it is intended that the term also encompass, as alternative embodiments, the phrases “consisting essentially of” and “consisting of”, where “consisting of” excludes any element or step not specified and “consisting essentially of” permits the inclusion of additional un-recited elements or steps that do not materially affect the basic and novel characteristics of the composition or method under consideration.

As used herein, the term “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include: hydrocarbon substituents, including aliphatic, alicyclic, and aromatic substituents; substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent; and hetero substituents, that is, substituents which similarly have a predominantly hydrocarbon character but contain other than carbon in a ring or chain. A more detailed definition of the term “hydrocarbyl substituent” or “hydrocarbyl group” is described in paragraphs [0118] to [0119] of International Publication WO2008147704, or a similar definition in paragraphs [0137] to [0141] of published application US 2010-0197536.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a lubricating oil composition, a method of improving air release in a functional fluid, such as a lubricating oil, and a method of lubricating a mechanical device using the lubricating oil composition as disclosed herein. Various preferred features and embodiments will be described below by way of non-limiting illustrations.

Oils of Lubricating Viscosity

One component (a) of the disclosed technology is an oil of lubricating viscosity, also referred to as a base oil. The base oil may be selected from any of the base oils in Groups I-V of the American Petroleum Institute (API) Base Oil Interchangeability Guidelines, namely

Base Oil Category Sulfur (%) Saturates (%) Viscosity Index Group I >0.03 and/or <90 80 to 120 Group II ≤0.03 and ≥90 80 to 120 Group III ≤0.03 and ≥90 >120 Group IV All polyalphaolefins (PAOs) Group V All others not included in Groups I, II, III or IV Groups I, II and III are mineral oil base stocks. The oil of lubricating viscosity can include natural or synthetic oils and mixtures thereof. Mixture of mineral oil and synthetic oils, e.g., polyalphaolefin oils and/or polyester oils, may be used.

Natural oils include animal oils and vegetable oils (e.g. vegetable acid esters) as well as mineral lubricating oils such as liquid petroleum oils and solvent-treated or acid treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffinic-naphthenic types. Hydrotreated or hydrocracked oils are also useful oils of lubricating viscosity. Oils of lubricating viscosity derived from coal or shale are also useful.

Synthetic oils include hydrocarbon oils and halosubstituted hydrocarbon oils such as polymerized and interpolymerized olefins and mixtures thereof, alkylbenzenes, polyphenyl, alkylated diphenyl ethers, and alkylated diphenyl sulfides and their derivatives, analogs and homologues thereof. Alkylene oxide polymers and interpolymers and derivatives thereof, and those where terminal hydroxyl groups have been modified by, e.g., esterification or etherification, are other classes of synthetic lubricating oils. Other suitable synthetic lubricating oils comprise esters of dicarboxylic acids and those made from C5 to C12 monocarboxylic acids and polyols or polyol ethers. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids, polymeric tetrahydrofurans, silicon-based oils such as polyalkyl-, polyaryl-, polyalkoxy-, or polyaryl-oxy-siloxane oils, and silicate oils.

Other synthetic oils include those produced by Fischer-Tropsch reactions, typically hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment oils may be prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure as well as other gas-to-liquid oils.

Unrefined, refined and rerefined oils, either natural or synthetic (as well as mixtures thereof) of the types disclosed hereinabove can be used. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Rerefined oils often are additionally processed to remove spent additives and oil breakdown products.

In some embodiments the industrial lubricant composition may also include a minor amount of one or more non-synthetic base oils. Examples of these non-synthetic base oils include any of those described herein, including API Group I, Group II, or Group III base oils.

The amount of the oil of lubricating viscosity present is typically the balance remaining after subtracting from 100 wt % the sum of the amount of the compounds of the invention and the other performance additives. In one embodiment, the amount of the oil of lubricating viscosity present is typically the balance remaining after subtracting from 100% by weight the sum of the amount of the ethylene/α-olefin copolymer and/or the additive comprising the reaction product of a hydroxy-substituted triester of a phosphorothioic acid with an inorganic phosphorus reagent selected from the class consisting of phosphorous acids, phosphorus oxides, and phosphorus halides and neutralizing a substantial portion of said acidic intermediate with an amine and any other optional performance additives in the composition.

The oil of lubricating viscosity can be present in a major amount, for a lubricant composition, or in a concentrate forming amount, for a concentrate and/or additive composition. The industrial lubricant composition of the invention may be either lubricant compositions or concentrate and/or additive compositions.

In a fully formulated lubricating oil composition in accordance with the present invention, the oil of lubricating viscosity is generally present in a major amount (i.e. an amount greater than 50 percent by weight). Typically, the oil of lubricating viscosity is present in an amount of 75 to 98 percent by weight, and often greater than 80 percent by weight of the overall composition.

The various described oils of lubricating viscosity may be used alone or in combinations. The oil of lubricating viscosity (considering all oil present) may be used in the described industrial lubricant compositions in the range of about 40 or 50 percent by weight to about 99 percent by weight, or from a minimum of 49.8, 70, 85, 93, 93.5 or even 97 up to a maximum of 99.8, 99, 98.5, 98 or even 97 percent by weight.

In still other embodiments the oil of lubricating viscosity may be used from 60 to 97, or from 80 to 97, or even from 85 to 97 percent by weight. Put another way, the compositions described herein may contain at least 60, 80, or even 85 percent by weight oil of lubricating viscosity.

In concentrate compositions, typically the amount of additives and other components remains the same, but the amount of oil of lubricating viscosity is reduced, in order to make the composition more concentrated and more efficient to store and/or transport. A person skilled in the art would be able to easily adjust the amount of oil of lubricating viscosity present in order to provide a concentrate and/or additive composition.

The Ethylene/α-Olefin Copolymer

One component in the lubricating oil composition of the present invention is an ethylene α-olefin copolymer. The ethylene α-olefin copolymer includes those with a backbone containing 1 to 3 different α-olefin monomers (beside the ethylene monomer), in one embodiment 1 to 3 different α-olefin monomers and in yet another embodiment 1 α-olefin monomer in addition to the ethylene monomer. The α-olefin monomers include 3 to 20, and in other embodiments 3 to 12, or 3 to 10, or 3 to 6, or 3 to 4 carbon atoms, and in another embodiment 3 carbon atoms (i.e., propylene). The olefin may be an alpha olefin of the above listed number of carbon atoms.

The ethylene α-olefin copolymer will have greater than 5 percent by weight ethylene monomer units, and in some embodiments at least 10 percent and up to 90 percent, or 15 to 85, or 20 to 80, or 30 to 50 percent by weight ethylene monomer units. In certain embodiments the amount of ethylene monomer will be 30-50 weight percent; in other embodiments the amount of ethylene monomer will be 75 to 85, or 79 to 81, weight percent. Otherwise expressed, the amount of ethylene monomer may be 15 to 90 or 25 to 85 or 40 to 60 or 45 to 55 mole percent.

The ethylene olefin copolymer thus includes an ethylene monomer and at least one other co-monomer derived from an alpha-olefin having the formula H⁻²C═CHR³, wherein R³ is a hydrocarbyl group, in one embodiment an alkyl radical containing 1 to 18, 1 to 12, 1 to 10, 1 to 6 or 1 to 3 carbon atoms. The hydrocarbyl group includes an alkyl radical that has a straight chain, a branched chain, or mixtures thereof.

Examples of suitable co-monomers include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-penta-decene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene or mixtures thereof. The co-monomer may be 1-butene, propylene or mixtures thereof. Examples of α-olefin copolymers include ethylene-propylene copolymers and ethylene-1-butene copolymers and mixtures thereof.

The polymer (c) may have a kinematic viscosity at 100° C. of at least 35 or at least 50 or at least 100 or at least 500 mm²/s at 100° C. In certain embodiments the polymer (c) may have a kinematic viscosity at 100° C. of at least about 500 or at least about 1000 mm²/s or 1500 mm²/s or 2000 mm²/s, which feature will distinguish it from similar materials of much lower viscosity that might be used as base oils. The polymer may have a number average molecular weight of 1000 to 8000, or 1000 to 5000, or 1300 to 8000, or 1500 to 3000, or 1800 to 2500, or about 2000, or 2500 to 5000, or 3500 to 4500, or about 4000. Its polydispersity (Mw/Mn) may be in the range of 1.3 to 4 or 1.4 to 3 or 1.4 to 2. It may be prepared by known methods by polymerization of (typically) ethylene and an alpha olefin such as propylene using an AlCl₃ or BF₃ catalyst or by other known methods.

The lubricating composition of the present invention also includes an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester.

The thiophosphoric acid ester is also known as thiophosphoric acid (needed to link to previous patents) and has one or more sulfur to phosphorus bonds. The thiophosphoric acid ester has one or more ester groups. Inorganic phosphorus agents include phosphorus acids, phosphorus oxides or phosphorus halides. The hydroxyl-substituted ester of thiophosphoric acid may be derived from mono- or dithiophosphoric acid esters containing one or more ester groups. The amine salt of a hydrocarbyl thiophosphoric acid ester has one or more sulfur to phosphorus bonds. The amine salt of a hydrocarbyl thiophosphoric acid ester may contain one or more ester groups. In one embodiment, the sulfur-containing phosphorus acid ester is referred to as a thiophosphorus acid salt thereof. The thiophosphoric acid or salt may be prepared by reacting one or more phosphorus sulfides with alcohols, such as those described above. Useful phosphorus sulfide-containing sources include phosphorus pentasulfide, phosphorus sesquisulfide, phosphorus heptasulfide and the like. Dithiophosphoric acid esters are also referred to generally as dithiophosphates.

The thiophosphoric acid ester may be prepared by reacting one or more phosphorus sulfide sources with alcohols. Useful phosphorus sulfides sources include phosphorus sulfide, phosphorus sesquisulfide, phosphorus heptasulfide and the like. The alcohols generally contain from one to about 30, or from two to about 24, or from about 3 to about 12, or up to about 8 carbon atoms. Alcohols used to prepare the thiophosphoric acid esters include butyl, amyl, 2-ethylhexyl, hexyl, octyl, oleyl, and cresol alcohols. Examples of commercially available alcohols include Alfol 810 (a mixture of primarily straight chain, primary alcohols having from 8 to 10 carbon atoms); Alfol 1218 (a mixture of synthetic, primary, straight-chain alcohols containing 12 to 18 carbon atoms); Alfol 20+ alcohols (mixtures of C18-C28 primary alcohols having mostly C20 alcohols as determined by GLC (gas-liquid-chromatography); and Alfol 22+ alcohols (C18-C28 primary alcohols containing primarily C22 alcohols). Alfol alcohols are available from Continental Oil Company. Another example of a commercially available alcohol mixtures are Adol 60 (about 75% by weight of a straight chain C22 primary alcohol, about 15% of a C20 primary alcohol and about 8% of C18 and C24 alcohols) and Adol 320 (oleyl alcohol). The Adol alcohols are marketed by Ashland Chemical.

A variety of mixtures of monohydric fatty alcohols derived from naturally occurring triglycerides and ranging in chain length of from C8 to C18 are available from Procter & Gamble Company. These mixtures contain various amounts of fatty alcohols containing mainly 12, 14, 16 or 18 carbon atoms. For example, CO-1214 is a fatty alcohol mixture containing 0.5% of C10 alcohol, 66.0% of C12 alcohol, 26.0% of C14 alcohol and 6.5% of C16 alcohol.

Another group of commercially available mixtures include the “Neodol” products available from Shell Chemical Co. For example, Neodol 23 is a mixture of C12 and C13 alcohols; Neodol 25 is a mixture of C12 and C15 alcohols; and Neodol 45 is a mixture of C14 to C15 linear alcohols. Neodol 91 is a mixture of C9, C10 and C11 alcohols.

Fatty vicinal diols also are useful and these include those available from Ashland Oil under the general trade designation Adol 114 and Adol 158. The former is derived from a straight chain alpha-olefin fraction of C11-C14, and the latter is derived from a C15-C18 alpha-olefin fraction.

In one embodiment, the thiophosphoric acid is a monothiophosphoric acid. Monothiophosphoric acids may be prepared by the reaction of a sulfur source with a dihydrocarbyl phosphite. The sulfur source may for instance be elemental sulfur, or a sulfide, such as a sulfur-coupled olefin or a sulfur-coupled dithiophosphate. Elemental sulfur is a good sulfur source. The preparation of monothiophosphoric acids is disclosed in U.S. Pat. No. 4,755,311 and PCT Publication WO 87/07638, incorporated herein by reference for their disclosure of monothiophosphoric acids, sulfur sources, and the process for making monothiophosphoric acids. Monothiophosphoric acids may also be formed in the lubricant blend by adding a dihydrocarbyl phosphite to a lubricating composition containing a sulfur source, such as a sulfurized olefin. The phosphite may react with the sulfur source under blending conditions (i.e., temperatures from about 30° C. to about 100° C., or higher) to form the monothiophosphoric acid.

In another embodiment, the hydroxyl-substituted ester of thiophosphoric acid is a dithiophosphoric acid or phosphorodithioic acid. The dithiophosphoric acid may be represented by the formula (R7O)2PSSH, wherein each R7 is independently a hydrocarbyl group containing from about 3 to about 30, or from about 3 up to about 18, or from about 4 up to about 12, or up to about 8 carbon atoms. Examples of R7 include isopropyl, isobutyl, n-butyl, sec-butyl, amyl, n-hexyl, methylisobutyl carbinyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, behenyl, decyl, dodecyl, tridecyl, alkylphenyl groups, or mixtures thereof. Illustrative lower alkylphenyl R7 groups include butylphenyl, amylphenyl, and heptylphenyl and mixtures thereof. Examples of mixtures of R7 groups include: 1-butyl and 1-octyl; 1-pentyl and 2-ethyl-1-hexyl; isobutyl and n-hexyl; isobutyl and isoamyl; 2-propyl and 2-methyl-4-pentyl; isopropyl and sec-butyl; and isopropyl and isooctyl.

In one embodiment, the hydroxyl-substituted ester of thiophosphoric acid is a phosphorus ester prepared by reacting one or more dithiophosphoric acid esters with an epoxide or a glycol. This reaction product may be used alone, or further reacted with a phosphorus acid, anhydride, or lower ester. The epoxide is generally an aliphatic epoxide or a styrene oxide. Examples of useful epoxides include ethylene oxide, propylene oxide, butene oxide, octene oxide, dodecene oxide, styrene oxide, etc. Propylene oxide is particularly useful. The glycols may be aliphatic glycols, having from 1 to about 12, or from about 2 to about 6, or from about 2 to about 3 carbon atoms, or aromatic glycols. Glycols include ethylene glycol, propylene glycol, catechol, resorcinol, and the like.

The inorganic phosphorus reagent useful in the reaction with the hydroxyl-substituted ester of thiophosphoric acid is preferably phosphorus pentoxide. Other phosphorus oxides such as phosphorus trioxide and phosphorus tetroxide likewise are useful. Also useful are phosphorus acids, and phosphorus halides. They are exemplified by phosphoric acid, pyrophosphoric acid, metaphosphoric acid, hypophosphoric acid, phosphorous acid, pyrophosphorous acid, metaphosphorous acid, hypophosphorous acid, phosphorus trichloride, phosphorus tribromide, phosphorus pentachloride, monobromophosphorus tetrachloride, phosphorus oxychloride, and phosphorus triiodide.

The reaction of the hydroxyl-substituted ester of thiophosphoric acid with the inorganic phosphorus reagent results in an acidic phosphoric acid intermediate. The chemical constitution of the acidic phosphoric acid intermediate depends to a large measure on the nature of the inorganic phosphorus reagent used.

The dithiophosphoric acids, glycols, epoxides, inorganic phosphorus reagents and methods of reacting the same are described in U.S. Pat. Nos. 3,197,405 and 3,544,465, incorporated herein by reference for their disclosure to these.

The amine salt of a hydrocarbyl thiophosphoric acid ester is prepared by reacting the acidic phosphoric acid intermediate with ammonia or a basic nitrogen compound, such as an amine or a nitrogen containing dispersant. The salts may be formed separately, and then the salt of the hydrocarbyl thiophosphoric acid ester may be added to the lubricating composition. Alternatively, the salts may also be formed in situ when the acidic phosphorus acid ester is blended with other components to form a fully formulated lubricating composition.

The ammonium salts of the hydrocarbyl thiophosphoric acid esters may be formed from ammonia, or an amine, or mixtures thereof. These amines may be monoamines or polyamines. Useful amines include those disclosed in U.S. Pat. No. 4,234,435 at Col. 21, line 4 to Col. 27, line 50, incorporated herein by reference.

The monoamines generally contain from 1 to about 24, or from 1 to about 12, or from 1 to about 6 carbon atoms. Examples of monoamines include methylamine, ethylamine, propylamine, butylamine, 2-ethylhexylamine, octylamine, and dodecylamine. Examples of secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, methylbutylamine, ethylhexylamine, etc. Tertiary amines include trimethylamine, tributylamine, methyldiethylamine, ethyldibutylamine, etc.

In one embodiment, the amine is a fatty (C8-30) amine such as n-octylamine, n-decylamine, n-dodecylamine, n-hexadecylamine, n-octadecylamine, oleyamine, etc. Also fatty amines include “Armeen” amines (products available from Akzo Chemicals, Chicago, Ill.), such Armeen C, Armeen O, Armeen T, and Armeen S, wherein the letter designates the fatty group, such as coco, oleyl, tallow, or stearyl groups.

Other useful amines include primary ether amines, such as those represented by the formula, R″(ORN)xNH2, wherein RN is a divalent alkylene group having about 2 to about 6 carbon atoms; x is a number from 1 to about 150, or from about 1 to about 5, or 1; and R″ is a hydrocarbyl group of about 5 to about 150 carbon atoms. An example of an ether amine is available under the name SURFAM® amines produced and marketed by Mars Chemical Company, Atlanta, Ga. Useful etheramines are exemplified by those identified as SURFAM P14B (decyloxypropylamine), SURFAM P16A (linear C16), SURFAM P17B (tridecyloxypropylamine). The carbon chain lengths (i.e., C14, etc.) of the SURFAMS described above and used hereinafter are approximate and include the oxygen ether linkage.

In one embodiment, the amine is a tertiary-aliphatic primary amine. Generally, the aliphatic group, generally an alkyl group, contains from about 4 to about 30, or from about 6 to about 24, or from about 8 to about 22 carbon atoms. Such amines are illustrated by t-butylamine, t-hexylamine, 1-methyl-1-amino-cyclohexane, t-octylamine, t-decylamine, t-dodecylamine, t-tetradecylamine, t-hexadecylamine, t-octadecylamine, t-tetracosanyl amine, and t-octacosanylamine.

The amine may be mixtures of tertiary aliphatic amines such as “Primene 81R” (a mixture of C11-C14 tertiary alkyl primary amines) and “Primene JMT” (a mixture of C18-C22 tertiary alkyl primary amines). These amines are available from Rohm and Haas Company. The tertiary aliphatic primary amine useful for the purposes of this invention and methods for their preparation are described in U.S. Pat. No. 2,945,749, incorporated by reference for its teaching in this regard.

In one embodiment, the amine may be a hydroxyamine. Typically, the hydroxyamines are primary, secondary, or tertiary alkanol amines or mixtures thereof. Such amines can be represented by the formulae: H2)N)R′)OH, H(R′1)N)R′)OH, and (R′1)2)N)R′)OH, wherein each R′1 is independently a hydrocarbyl group having from 1 to about 8 carbon atoms or hydroxyhydrocarbyl group having from one to about eight carbon atoms, or from one to about four, and R′ is a divalent hydrocarbyl group of about 2 to about 18 carbon atoms, or from 2 to about 4. The group —R′—OH in such formulae represents the hydroxyhydrocarbyl group. R′ can be an acyclic, alicyclic or aromatic group. Typically, R′ is an acyclic straight or branched alkylene group, such as an ethylene, 1,2-propylene, 1,2-butylene, and 1,2-octadecylene groups. Where two R′1 groups are present in the same molecule they can be joined by a direct carbon-to-carbon bond or through a heteroatom (e.g., oxygen, nitrogen or sulfur) to form a 5-, 6-, 7- or 8-membered ring structure. Typically, however, each R′1 is independently a methyl, ethyl, propyl, butyl, pentyl or hexyl group. Examples of these alkanolamines include mono-, di-, and triethanolamine, diethylethanolamine, ethyl ethanolamine, butyldiethanolamine, etc.

The hydroxyamines may also be an ether N-(hydroxyhydrocarbyl)amine. These are hydroxypoly(hydrocarbyloxy) analogs of the above-described hydroxyamines (these analogs also include hydroxyl-substituted oxyalkylene analogs). Such N-(hydroxyhydrocarbyl) amines can be conveniently prepared by reaction of one or more of the epoxides described herein with afore-described amines and may be represented by the formulae: H2N)(R′O)x)H, H(R′1))N)(R′O)x)H, and (R′1)2)N)(R′O)x)H, wherein x is a number from about 2 to about 15 and R′1 and R′ are as described above. R′1 may also be a hydroxypoly(hydrocarbyloxy) group. Useful hydroxyhydrocarbyl amines include 2-hydroxyethylhexylamine; 2-hydroxyethyloctylamine; 2-hydroxyethylpentadecylamine; 2-hydroxyethyloleylamine; 2-hydroxyethylsoyamine; bis(2-hydroxyethyl)hexyl amine; bis(2-hydroxyethyl)oleylamine; and mixtures thereof.

In one embodiment, the amine may be a hydroxyhydrocarbyl amine. These hydroxyhydrocarbyl amines are available from the Akzo Chemical Division of Akzona, Inc., Chicago, Ill., under the general trade designations “Ethomeen” and “Propomeen.” Specific examples of such products include: Ethomeen C/15; Ethomeen C/20 and C/25; Ethomeen O/12; Ethomeen S/15 and S/20; Ethomeen T/12, T/15 and T/25; and Propomeen O/12.

The amine may also be a polyamine. The polyamines include alkoxylated diamines, fatty polyamine diamines, alkylenepolyamines, hydroxy containing polyamines, condensed polyamines, arylpolyamines, and heterocyclic polyamines. Commercially available examples of alkoxylated diamines include Ethoduomeen T/13 and T/20, which are ethylene oxide condensation products of N-tallowtrimethylenediamine containing 3 and 10 moles of ethylene oxide per mole of diamine, respectively.

In another embodiment, the polyamine is a fatty diamine. The fatty diamines include mono- or dialkyl, symmetrical or asymmetrical ethylenediamines, propanediamines (1,2 or 1,3), and polyamine analogs of the above. Suitable commercial fatty polyamines are Duomeen C (N-coco-1,3-diaminopropane), Duomeen S (N-soya-1,3-diaminopropane), Duomeen T (N-tallow-1,3-diaminopropane), and Duomeen O (N-oleyl-1,3-diaminopropane). “Duomeens” are commercially available from Armak Chemical Co., Chicago, Ill.

In another embodiment, the amine is an alkylenepolyamine. Alkylenepolyamines are represented by the formula HR4N-(Alkylene-N)n-(R4)2, wherein each R4 is independently hydrogen; or an aliphatic or hydroxy-substituted aliphatic group of up to about 30 carbon atoms; n is a number from 1 to about 10, or from about 2 to about 7, or from about 2 to about 5; and the “Alkylene” group has from 1 to about 10 carbon atoms, or from about 2 to about 6, or from about 2 to about 4. In another embodiment, R4 is defined the same as R′1 above. Such alkylenepolyamines include methylenepolyamines, ethylenepolyamines, butylenepolyamines, propylenepolyamines, pentylenepolyamines, etc. Specific examples of such polyamines are ethylenediamine, triethylenetetramine, tris-(2-aminoethyl)amine, propylenediamine, trimethylenediamine, tripropylenetetramine, triethylenetetriamine, tetraethylenepentamine, hexaethyleneheptamine, pentaethylenehexamine, etc. Higher homologs obtained by condensing two or more of the above-noted alkyleneamines are similarly useful as are mixtures of two or more of the aforedescribed polyamines.

In one embodiment, the polyamine is an ethylenepolyamine. Such polyamines are described in detail under the heading Ethylene Amines in Kirk Othmer's “Encyclopedia of Chemical Technology,” 2d Edition, Vol. 7, pages 22-37, Interscience Publishers, New York (1965). Ethylenepolyamines are often a complex mixture of polyalkylenepolyamines including cyclic condensation products. Other useful types of polyamine mixtures are those resulting from stripping of the above-described polyamine mixtures to leave, as residue, what is often termed “polyamine bottoms”. In general, alkylenepolyamine bottoms can be characterized as having less than 2%, usually less than 1% (by weight) material boiling below about 200° C. A typical sample of such ethylenepolyamine bottoms obtained from the Dow Chemical Company of Freeport, Texas designated “E-100” has a specific gravity at 15.6° C. of 1.0168, a percent nitrogen by weight of 33.15 and a viscosity at 40° C. of 121 centistokes. Gas chromatography analysis of such a sample contains about 0.93% “Light Ends” (most probably diethyl enetriamine), 0.72% triethylenetetriamine, 21.74% tetraethylenepentamine and 76.61% pentaethylenehexamine and higher analogs. These alkylenepolyamine bottoms include cyclic condensation products such as piperazine and higher analogs of diethylenetriamine, triethylenetetramine and the like. These alkylenepolyamine bottoms may be reacted solely with the acylating agent or they may be used with other amines, polyamines, or mixtures thereof.

Another useful polyamine is a condensation reaction between at least one hydroxy compound with at least one polyamine reactant containing at least one primary or secondary amino group. The hydroxy compounds include polyhydric alcohols and amines. The polyhydric alcohols are described below. In one embodiment, the hydroxy compounds are polyhydric amines. Polyhydric amines include any of the above-described monoamines reacted with an alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, etc.) having from two to about 20 carbon atoms, or from 2 to about 4. Examples of polyhydric amines include tri-(hydroxypropyl)amine, tris-(hydroxymethyl)amino methane, 2-amino-2-methyl-1,3-propanediol, N,N,N′,N′-tetrakis (2-hydroxypropyl) ethyl enediamine, and N,N,N′,N′-tetrakis (2-hydroxyethyl) ethylenediamine. Tris(hydroxymethyl) aminomethane (THAM) is particularly useful.

Polyamines that may react with the polyhydric alcohol or amine to form the condensation products or condensed amines, are described above. Preferred polyamines include triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), and mixtures of polyamines such as the above-described “amine bottoms.” The condensation reaction of the polyamine reactant with the hydroxy compound is conducted at an elevated temperature, usually from about 60° C. to about 265° C., or from about 220° C. to about 250° C. in the presence of an acid catalyst.

The amine condensates and methods of making the same are described in PCT publication WO 86/05501 and U.S. Pat. No. 5,230,714 (Steckel), incorporated by reference for its disclosure to the condensates and methods of making. A particularly useful amine condensate is prepared from HPA Taft Amines (amine bottoms available commercially from Union Carbide Co. with typically 34.1% by weight nitrogen and a nitrogen distribution of 12.3% by weight primary amine, 14.4% by weight secondary amine and 7.4% by weight tertiary amine), and tris(hydroxymethyl)aminomethane (THAM).

In another embodiment, the polyamines are polyoxyalkylene polyamines, e.g. polyoxyalkylene diamines and polyoxyalkylene triamines, having average molecular weights ranging from about 200 to about 4000, or from about 400 to about 2000. The polyoxyalkylene polyamines are commercially available and may be obtained, for example, from the Jefferson Chemical Company, Inc. under the trade name “Jeffamines D-230, D-400, D-1000, D-2000, T-403, etc.” U.S. Pat. Nos. 3,804,763 and 3,948,800 are expressly incorporated herein by reference for their disclosure of such polyoxyalkylene polyamines and acylated products made therefrom.

In another embodiment, the polyamines are hydroxy-containing polyamines. Hydroxy-containing polyamine analogs of hydroxy monoamines, particularly alkoxylated alkylenepolyamines, e.g., N,N-(diethanol)ethylene diamines can also be used. Such polyamines can be made by reacting the above-described alkylene amines with one or more of the alkylene oxides described herein. Similar alkylene oxide-alkanol amine reaction products may also be used such as the products made by reacting the above described primary, secondary or tertiary alkanol amines with ethylene, propylene or higher epoxides in a 1.1 to 1.2 molar ratio. Specific examples of hydroxy-containing polyamines include N-(2-hydroxyethyl) ethyl enediamine, N,N′-bis(2-hydroxyethyl)-ethylenediamine, 1-(2-hydroxyethyl)piperazine, mono(hydroxypropyl)-substituted tetraethylenepentamine, N-(3-hydroxybutyl)-tetramethylene diamine, etc.

In another embodiment, the polyamine is a heterocyclic polyamine. The heterocyclic polyamines include aziridines, azetidines, azolidines, tetra- and dihydropyridines, pyrroles, indoles, piperidines, imidazoles, di- and tetrahydroimidazoles, piperazines, isoindoles, purines, morpholines, thiomorpholines, N-aminoalkylmorpholines, N-aminoalkylthiomorpholines, N-aminoalkylpiperazines, N,N′-diaminoalkylpiperazines, azepines, azocines, azonines, azecines and tetra-, di- and perhydro derivatives of each of the above and mixtures of two or more of these heterocyclic amines.

The following examples relate to amine salts of hydrocarbyl thiophosphoric acid esters. Unless the context indicates otherwise, temperatures are in degrees Celsius, pressure is atmospheric, and the parts and percentages are by weight

The additive may be referred to as an anti-wear additive.

Viscosity grades are used to describe the various categories of fluid viscosity as summarized in Table 1 below:

Viscosity Limits of ISO VG Categories According to ISO 3448 Iso 3448 Typical Minimum Maximum Viscosity Viscosity Viscosity Viscosity Grades cSt @ 40° C. cSt @ 40° C. cSt @ 40° C. ISO VG 15 15.0 13.5 16.5 ISO VG 22 22.0 19.8 24.2 ISO VG 32 32.0 28.8 35.2 ISO VG 46 46.0 41.4 50.6 ISO VG 68 68.0 61.2 74.8 ISO VG 100 100.0 90.0 110.0 ISO VG 150 150.0 135.0 165.0 ISO VG 220 220.0 198.0 242.0 ISO VG 320 320.0 288.0 352.0

Air release performance may be measured by a number of tests, for example ASTM D3427, which measures air release from a lubricating oil at 50° C. Viscosity may be measured by a number of tests including ASTM D445 and DIN EN ISO 3104.

It has been observed that the lubricating oil compositions comprising an oil of lubricating viscosity, an ethylene/α-olefin copolymer, as described herein, and an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester, in particular wherein the additive is obtained by reacting a phosphorous sulfide with one or more alcohols having about 3 to about 13 carbon atoms to form a thiophosphoric acid ester, further reacting the thiophosphoric acid ester with an alkylene oxide to form a hydroxyl-substituted ester of thiophosphoric acid, and further reacting said hydroxyl-substituted ester of thiophosphoric acid with a phosphorous oxide to form a an acidic phosphoric acid intermediate, and salting said acidic phosphoric acid intermediate with one or more amines wherein said amines contain one or more hydrocarbyl groups having from 2 to 30 carbon atoms unexpectedly show improved air release properties while maintaining the viscosity grade of the lubricating oil, indicating a synergistic effect between the ethylene/α-olefin copolymer and the additive.

Other Additives

The compositions of the invention may include other performance additives or an industrial additive package, which may also be referred to as an industrial lubricant additive package. In other words, the compositions of the invention are designed to be industrial lubricants, or additive packages for making the same. The present invention does not relate to automotive gear lubricants or other lubricating compositions.

In some embodiments the industrial lubricant additive package includes a demulsifier, a dispersant, and a metal deactivator. Any combination of conventional additive packages designed for industrial application may be used. The invention in some embodiments specifies the additive package is essentially free, if not completely free of, the compatibiliser described herein, or at least do not contain the type of compatibiliser specified by the invention in the amounts specified.

The additives which may be present in the industrial additive package include a foam inhibitor, a demulsifier, a pour point depressant, an antioxidant, a dispersant, a metal deactivator (such as a copper deactivator), an antiwear agent, an extreme pressure agent, a viscosity modifier, or some mixture thereof. The additives may each be present in the range from 50, 75, 100 or even 150 ppm up to 5, 4, 3, 2 or even 1.5 percent by weight, or from 75 ppm to 0.5 percent by weight, from 100 ppm to 0.4 percent by weight, or from 150 ppm to 0.3 percent by weight, where the percent by weight values are with regards to the overall lubricant composition. In other embodiments the overall industrial additive package is present from 1 to 20, or from 1 to 10 percent by weight of the overall lubricant composition. However it is noted that some additives, including viscosity modifying polymers, which may alternatively be considered as part of the base fluid, may be present in higher amounts including up to 30, 40, or even 50% by weight when considered separate from the base fluid. The additives may be used alone or as mixtures thereof.

The compositions of the invention may also include antifoams, also known as foam inhibitors, which include but are not limited to organic silicones and non-silicon foam inhibitors. Examples of organic silicones include dimethyl silicone and polysiloxanes. Examples of non-silicon foam inhibitors include but are not limited to polyethers, polyacrylates and mixtures thereof as well as copolymers of ethyl acrylate, 2-ethylhexylacrylate, and optionally vinyl acetate. In some embodiments the antifoam is a polyacrylate. Antifoams may be present in the composition from 0.001 to 0.012 or 0.004 pbw or even 0.001 to 0.003 pbw.

The compositions of the invention may also include demulsifiers, which include but are not limited to derivatives of propylene oxide, ethylene oxide, polyoxyalkylene alcohols, alkyl amines, amino alcohols, diamines or polyamines reacted sequentially with ethylene oxide or substituted ethylene oxides or mixtures thereof. Examples of demulsifiers include polyethylene glycols, polyethylene oxides, polypropylene oxides, (ethylene oxide-propylene oxide) polymers and mixtures thereof. In some embodiments the demulsifiers are polyethers. Demulsifiers may be present in the composition from 0.002 to 0.2 pbw.

The compositions of the invention may also include pour point depressants, which include but are not limited to esters of maleic anhydride-styrene copolymers, polymethacrylates; polyacrylates; polyacryl amides; condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkyl fumarates, vinyl esters of fatty acids, ethylene-vinyl acetate copolymers, alkyl phenol formaldehyde condensation resins, alkyl vinyl ethers and mixtures thereof.

The compositions of the invention may also include a rust inhibitor, other than some of the additives described above. Suitable rust inhibitors include hydrocarbyl amine salts of dialkyldithiophosphoric acid, hydrocarbyl amine salts of hydrocarbyl arenesulphonic acid, fatty carboxylic acids or esters thereof, an ester of a nitrogen-containing carboxylic acid, an ammonium sulfonate, an imidazoline, mono-thio phosphate salts or esters, or any combination thereof; or mixtures thereof. Examples of hydrocarbyl amine salts of dialkyldithiophosphoric acid of the invention include but are not limited to those described above, as well as the reaction product(s) of diheptyl or dioctyl or dinonyl dithiophosphoric acids with ethylenediamine, morpholine or Primene™ 81R or mixtures thereof. Suitable hydrocarbyl amine salts of hydrocarbyl arenesulphonic acids used in the rust inhibitor package of the invention are represented by the formula:

wherein Cy is a benzene or naphthalene ring. R¹ is a hydrocarbyl group with about 4 to about 30, preferably about 6 to about 25, more preferably about 8 to about 20 carbon atoms. z is independently 1, 2, 3, or 4 and most preferably z is 1 or 2. R², R³ and R⁴ are the same as described above. Examples of hydrocarbyl amine salts of hydrocarbyl arenesulphonic acid of the invention include but are not limited to the ethylenediamine salt of dinonylnaphthalene sulfonic acid. Examples of suitable fatty carboxylic acids or esters thereof include glycerol monooleate and oleic acid. An example of a suitable ester of a nitrogen-containing carboxylic acid includes oleyl sarcosine. The rust inhibitors may be present in the range from 0.02 to 0.2, from 0.03 to 0.15, from 0.04 to 0.12, or from 0.05 to 0.1 percent by weight of the lubricating oil composition. The rust inhibitors of the invention may be used alone or in mixtures thereof.

The compositions of the invention may also include a metal deactivator. Metal deactivators are used to neutralise the catalytic effect of metal for promoting oxidation in lubricating oil. Suitable metal deactivators include but are not limited to triazoles, tolyltriazoles, a thiadiazole, or combinations thereof, as well as derivatives thereof. Examples include derivatives of benzotriazoles other than those described above, benzimidazole, 2-alkyldithiobenzimidazoles, 2-alkyldithiobenzothiazoles, 2-(N,N′-dialkyldithio-carbamoyl)benzothiazoles, 2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles, 2,5-bis(N,N′-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles, 2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof. These additives may be used from 0.01 to 0.25 percent by weight in the overall composition. In some embodiments the metal deactivator is a hydrocarbyl substituted benzotriazole compound. The benzotriazole compounds with hydrocarbyl substitutions include at least one of the following ring positions 1- or 2- or 4- or 5- or 6- or 7-benzotriazoles. The hydrocarbyl groups contain about 1 to about 30, preferably about 1 to about 15, more preferably about 1 to about 7 carbon atoms, and most preferably the metal deactivator is 5-methylbenzotriazole used alone or mixtures thereof. The metal deactivators may be present in the range from 0.001 to 0.5, from 0.01 to 0.04 or from 0.015 to 0.03 pbw of the lubricating oil composition. Metal deactivators may also be present in the composition from 0.002 or 0.004 to 0.02 pbw. The metal deactivator may be used alone or mixtures thereof.

The compositions of the invention may also include antioxidants, including (i) an alkylated diphenylamine, and (ii) a substituted hydrocarbyl mono-sulfide. In some embodiments the alkylated diphenylamines of the invention are bis-nonylated diphenylamine and bis-octylated diphenylamine. In some embodiments the substituted hydrocarbyl monosulfides include n-dodecyl-2-hydroxyethyl sulfide, 1-(tert-dodecylthio)-2-propanol, or combinations thereof. In some embodiments the substituted hydrocarbyl monosulfide is 1-(tert-dodecylthio)-2-propanol. The antioxidant package may also include sterically hindered phenols. Examples of suitable hydrocarbyl groups for the sterically hindered phenols include but are not limited to 2-ethylhexyl or n-butyl ester, dodecyl or mixtures thereof. Examples of methylene-bridged sterically hindered phenols include but are not limited to 4,4′-methylene-bis(6-tert-butyl o-cresol), 4,4′-methyl ene-bis(2-tert-amyl-o-cresol), 2,2′-methylene-bis(4-methyl-6-tert-butylphenol), 4,4′-methylene-bis(2,6-di-tertbutylphenol) or mixtures thereof.

The compositions of the invention may also include nitrogen-containing dispersants, for example a hydrocarbyl substituted nitrogen containing additive. Suitable hydrocarbyl substituted nitrogen containing additives include ashless dispersants and polymeric dispersants. Ashless dispersants are so-named because, as supplied, they do not contain metal and thus do not normally contribute to sulfated ash when added to a lubricant. However they may, of course, interact with ambient metals once they are added to a lubricant which includes metal-containing species. Ashless dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. Examples of such materials include succinimide dispersants, Mannich dispersants, and borated derivatives thereof.

The compositions of the invention may also include sulfur-containing compounds. Suitable sulfur-containing compounds include sulfurized olefins and polysulfides. The sulfurized olefin or polysulfides may be derived from isobutylene, butylene, propylene, ethylene, or some combination thereof. In some examples the sulfur-containing compound is a sulfurized olefin derived from any of the natural oils or synthetic oils described above, or even some combination thereof. For example the sulfurized olefin may be derived from vegetable oil.

The compositions of the invention may also include phosphorus containing compound, such as a fatty phosphite. The phosphorus containing compound can include a hydrocarbyl phosphite, a phosphoric acid ester, an amine salt of a phosphoric acid ester, or any combination thereof. In some embodiments the phosphorus containing compound includes a hydrocarbyl phosphite, an ester thereof, or a combination thereof. In some embodiments the phosphorus containing compound includes a hydrocarbyl phosphite. In some embodiments the hydrocarbyl phosphite is an alkyl phosphite. By alkyl it is meant an alkyl group containing only carbon and hydrogen atoms, however either saturated or unsaturated alkyl groups are contemplated or mixtures thereof. In some embodiments the phosphorus containing compound includes an alkyl phosphite that has a fully saturated alkyl group. In some embodiments the phosphorus containing compound includes an alkyl phosphite that has an alkyl group with some unsaturation, for example, one double bond between carbon atoms. Such unsaturated alkyl groups may also be referred to as alkenyl groups, but are included within the term “alkyl group” as used herein unless otherwise noted. In some embodiments the phosphorus containing compound includes an alkyl phosphite, a phosphoric acid ester, an amine salt of a phosphoric acid ester, or any combination thereof. In some embodiments the phosphorus containing compound includes an alkyl phosphite, an ester thereof, or a combination thereof. In some embodiments the phosphorus containing compound includes an alkyl phosphite. In some embodiments the phosphorus containing compound includes an alkenyl phosphite, a phosphoric acid ester, an amine salt of a phosphoric acid ester, or any combination thereof. In some embodiments the phosphorus containing compound includes an alkenyl phosphite, an ester thereof, or a combination thereof. In some embodiments the phosphorus containing compound includes an alkenyl phosphite. In some embodiments the phosphorus containing compound includes dialkyl hydrogen phosphites. In some embodiments the phosphorus-containing compound is essentially free of, or even completely free of, phosphoric acid esters and/or amine salts thereof. In some embodiments the phosphorus-containing compound may be described as a fatty phosphite. Suitable phosphites include those having at least one hydrocarbyl group with 4 or more, or 8 or more, or 12 or more, carbon atoms. Typical ranges for the number of carbon atoms on the hydrocarbyl group include 8 to 30, or 10 to 24, or 12 to 22, or 14 to 20, or 16 to 18. The phosphite may be a mono-hydrocarbyl substituted phosphite, a di-hydrocarbyl substituted phosphite, or a tri-hydrocarbyl substituted phosphite. In one embodiment the phosphite is sulphur-free i.e., the phosphite is not a thiophosphite. The phosphite having at least one hydrocarbyl group with 4 or more carbon atoms may be represented by the formulae:

wherein at least one of R⁶, R⁷ and R⁸ may be a hydrocarbyl group containing at least 4 carbon atoms and the other may be hydrogen or a hydrocarbyl group. In one embodiment R⁶, R⁷ and R⁸ are all hydrocarbyl groups. The hydrocarbyl groups may be alkyl, cycloalkyl, aryl, acyclic or mixtures thereof. In the formula with all three groups R⁶, R⁷ and R⁸, the compound may be a tri-hydrocarbyl substituted phosphite i.e., R⁶, R⁷ and R⁸ are all hydrocarbyl groups and in some embodiments may be alkyl groups. The alkyl groups may be linear or branched, typically linear, and saturated or unsaturated, typically saturated. Examples of alkyl groups for R⁶, R⁷ and R⁸ include octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, octadecenyl, nonadecyl, eicosyl or mixtures thereof. In some embodiments the fatty phosphite component of the invention, and/or the composition overall is essentially free of, or even completely free of phosphoric acid ester and/or amine salts thereof. In some embodiments the fatty phosphite comprises an alkenyl phosphite or esters thereof, for example esters of dimethyl hydrogen phosphite. The dimethyl hydrogen phosphite may be esterified, and in some embodiments transesterified, by reaction with an alcohol, for example oleyl alcohol.

The compositions of the invention may also include one or more phosphorous amine salts, but in amounts such that the additive package, or in other embodiments the resulting industrial lubricant compositions, contains no more than 1.0 percent by weight of such materials, or even no more than 0.75 or 0.6 percent by weight. In other embodiments the industrial lubricant additive packages, or the resulting industrial lubricant compositions, are essentially free of or even completely free of phosphorous amine salts.

The compositions of the invention may also include one or more antiwear additives and/or extreme pressure agents, one or more rust and/or corrosion inhibitors, one or more foam inhibitors, one or more demulsifiers, or any combination thereof.

In some embodiments the industrial gear lubricant additive packages, or the resulting industrial gear lubricant compositions, are essentially free of or even completely free of phosphorous amine salts, dispersants, or both.

In some embodiments the industrial lubricant additive packages, or the resulting industrial lubricant compositions, include a demulsifier, a corrosion inhibitor, a friction modifier, or combination of two or more thereof. In some embodiments the corrosion inhibitor includes a tolyltriazole. In still other embodiments the industrial additive packages, or the resulting industrial lubricant compositions, include one or more sulfurized olefins or polysulfides; one or more phosphorus amine salts; one or more thiophosphate esters, one or more thiadiazoles, tolyltriazoles, polyethers, and/or alkenyl amines; one or more ester copolymers; one or more carboxylic esters; one or more succinimide dispersants, or any combination thereof.

The industrial lubricant additive package may be present in the overall industrial lubricant from 1 to 5 percent by weight, or in other embodiments from 1, 1.5, or even 2 percent by weight up to 2, 3, 4, 5, 7 or even 10 percent by weight. Amounts of the industrial gear additive package that may be present in the industrial gear concentrate compositions of the invention are the corresponding amounts to the weight percent above, where the values are considered without the oil present (i.e. they may be treated as pbw values along with the actual amount of oil present).

The compositions of the invention may also include a derivative of a hydroxy-carboxylic acid. Suitable acids may include from 1 to 5 or 2 carboxy groups or from 1 to 5 or 2 hydroxy groups. In some embodiments the friction modifier is derivable from a hydroxy-carboxylic acid represented by the formula:

wherein: a and b may be independently integers of 1 to 5, or 1 to 2; X may be an aliphatic or alicyclic group, or an aliphatic or alicyclic group containing an oxygen atom in the carbon chain, or a substituted group of the foregoing types, said group containing up to 6 carbon atoms and having a+b available points of attachment; each Y may be independently —O—, >NH, or >NR³ or two Y's together representing the nitrogen of an imide structure R⁴—N<formed between two carbonyl groups; and each R³ and R⁴ may be independently hydrogen or a hydrocarbyl group, provided that at least one R¹ and R³ group may be a hydrocarbyl group; each R² may be independently hydrogen, a hydrocarbyl group or an acyl group, further provided that at least one —OR² group is located on a carbon atom within X that is α or β to at least one of the —C(O)—Y—R¹ groups, and further provided that at least on R² is hydrogen. The hydroxy-carboxylic acid is reacted with an alcohol and/or an amine, via a condensation reaction, forming the derivative of a hydroxy-carboxylic acid, which may also be referred to herein as a friction modifier additive. In one embodiment the hydroxy-carboxylic acid used in the preparation of the derivative of a hydroxy-carboxylic acid is represented by the formula:

wherein each R⁵ is independently H or a hydrocarbyl group, or wherein the R⁵ groups together form a ring. In one embodiment, where R⁵ is H, the condensation product is optionally further functionalized by acylation or reaction with a boron compound. In another embodiment the friction modifier is not borated. In any of the embodiments above, the hydroxy-carboxylic acid may be tartaric acid, citric acid, or combinations thereof, and may also be a reactive equivalent of such acids (including esters, acid halides, or anhydrides). The resulting friction modifiers may include imide, di-ester, di-amide, or ester-amide derivatives of tartaric acid, citric acid, or mixtures thereof. In one embodiment the derivative of hydroxycarboxylic acid includes an imide, a di-ester, a di-amide, an imide amide, an imide ester or an ester-amide derivative of tartaric acid or citric acid. In one embodiment the derivative of hydroxycarboxylic acid includes an imide, a di-ester, a di-amide, an imide amide, an imide ester or an ester-amide derivative of tartaric acid. In one embodiment the derivative of hydroxycarboxylic acid includes an ester derivative of tartaric acid. In one embodiment the derivative of hydroxycarboxylic acid includes an imide and/or amide derivative of tartaric acid. The amines used in the preparation of the friction modifier may have the formula RR′NH wherein R and R′ each independently represent H, a hydrocarbon-based radical of 1 or 8 to 30 or 150 carbon atoms, that is, 1 to 150 or 8 to 30 or 1 to 30 or 8 to 150 atoms. Amines having a range of carbon atoms with a lower limit of 2, 3, 4, 6, 10, or 12 carbon atoms and an upper limit of 120, 80, 48, 24, 20, 18, or 16 carbon atoms may also be used. In one embodiment, each of the groups R and R′ has 8 or 6 to 30 or 12 carbon atoms. In one embodiment, the sum of carbon atoms in R and R′ is at least 8. R and R′ may be linear or branched. The alcohols useful for preparing the friction modifier will similarly contain 1 or 8 to 30 or 150 carbon atoms. Alcohols having a range of carbon atoms from a lower limit of 2, 3, 4, 6, 10, or 12 carbon atoms and an upper limit of 120, 80, 48, 24, 20, 18, or 16 carbon atoms may also be used. In certain embodiments the number of carbon atoms in the alcohol-derived group may be 8 to 24, 10 to 18, 12 to 16, or 13 carbon atoms. The alcohols and amines may be linear or branched, and, if branched, the branching may occur at any point in the chain and the branching may be of any length. In some embodiments the alcohols and/or amines used include branched compounds, and in still other embodiments, the alcohols and amines used are at least 50%, 75% or even 80% branched. In other embodiments the alcohols are linear. In some embodiments, the alcohol and/or amine have at least 6 carbon atoms. Accordingly, certain embodiments of the invention employ the product prepared from branched alcohols and/or amines of at least 6 carbon atoms, for instance, branched C₆₋₁₈ or C₈₋₁₈ alcohols or branched C₁₂₋₁₆ alcohols, either as single materials or as mixtures. Specific examples include 2-ethylhexanol and isotridecyl alcohol, the latter of which may represent a commercial grade mixture of various isomers. Also, certain embodiments of the invention employ the product prepared from linear alcohols of at least 6 carbon atoms, for instance, linear C₆₋₁₈ or C₈₋₁₈ alcohols or linear C₁₂₋₁₆ alcohols, either as single materials or as mixtures. The tartaric acid used for preparing the tartrates, tartrimides, or tartramides of the invention can be the commercially available type (obtained from Sargent Welch), and it exists in one or more isomeric forms such as d-tartaric acid, l-tartaric acid, d,l-tartaric acid or meso-tartaric acid, often depending on the source (natural) or method of synthesis (e.g. from maleic acid). These derivatives can also be prepared from functional equivalents to the diacid readily apparent to those skilled in the art, such as esters, acid chlorides, anhydrides, etc. In other embodiments the friction modifier includes glycerol monooleate.

In some embodiments the additive package includes one or more corrosion inhibitors, one or more dispersants, one or more antiwear and/or extreme pressure additives, one or more extreme pressure agents, one or more antifoam agents, one or more detergents, and optionally some amount of base oil or similar solvent as a diluent. In some embodiments the additive package includes at least one friction modified and at least one demulsifier, and optionally one or more additional additives present as well.

The additional additives may be present in the overall industrial gear lubricant composition from 0.1 to 30 percent by weight, or from a minimum level of 0.1, 1 or even 2 percent by weight up to a maximum of 30, 20, 10, 5, or even 2 percent by weight, or from 0.1 to 30, from 0.1 to 20, from 1 to 20, from 1 to 10, from 1 to 5, or even about 2 percent by weight. These ranges and limits may be applied to each individual additional additive present in the composition, or to all of the additional additives present.

In one embodiment, a lubricant composition may be prepared by adding the ethylene/α-olefin copolymer as described herein to an oil of lubricating viscosity, optionally in the presence of an industrial additive package (as described herein). In another embodiment, a lubricant composition may be prepared by adding the ethylene/α-olefin copolymer and/or the additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester to an oil of lubricating viscosity, optionally in the presence of an industrial additive package (as described herein).

In one embodiment, the an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester, for example, an additive obtained by reacting a phosphorous sulfide with one or more alcohols having about 3 to about 13 carbon atoms to form a thiophosphoric acid ester, further reacting the thiophosphoric acid ester with an alkylene oxide to form a hydroxyl-substituted ester of thiophosphoric acid, and further reacting said hydroxyl-substituted ester of thiophosphoric acid with a phosphorous oxide to form a an acidic phosphoric acid intermediate, and salting said acidic phosphoric acid intermediate with one or more amines wherein said amines contain one or more hydrocarbyl groups having from 2 to 30 carbon atoms acts as the antiwear agent in the lubricating oil composition. In one embodiment, the lubricating oil composition comprises an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester and is substantially free of other antiwear performance additives.

INDUSTRIAL APPLICATION

The invention includes both industrial gear lubricant compositions and methods for improving air release in industrial gear lubricant compositions. In some embodiments the industrial lubricant compositions of the invention are industrial gear lubricant compositions.

The various ranges for the components described above can be applied to concentrate compositions by maintaining the same relative ratios between components (b) and (c), while adjustment the amount of (a), (that is the amount of (a) will be much lower in a concentrate composition compared to a lubricant composition). In such embodiments the percent by weight values for components (b) and (c) may be treated as parts by weight (pbw), with oil making up the balance of the concentrate composition, including anywhere from 0 or 0.1 or 0.5 or even 1 pbw up to 10, 20, 30 or even 40 or 50 pbw oil and/or base fluid.

The amount of each chemical component described is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, that is, on an active chemical basis, unless otherwise indicated. However, unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade.

In one embodiment the lubricant composition is an industrial gear oil. In some embodiments the industrial gear oil may be a Group I, Group II or Group III basestock as defined by the American Petroleum Institute. In some embodiments, the metal working oil may be mixed with Group IV or Group V basestock. In one embodiment the lubricating oil composition contains about 2% to about 17% by weight, for example, about 5% to about 17% or about 5% to about 11% by weight, based on the total weight of the lubricating oil composition of a ethylene/α-olefin copolymer and about 0.04% to about 0.20%, for example, about 0.04 to about 0.15% or even about 0.10% to about 0.15% by weight, based on the total weight of the lubricating oil composition of an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester.

In one embodiment, the lubricating composition of the present invention releases all entrapped air in about 25 minutes or less as measured by ASTM D3427 at 50° C. In another embodiment, the lubricating composition of the present invention releases all entrapped air from the lubricating composition in about 18 minutes or less as measured by ASTM D3427 at 50° C.

The following examples provide illustrations of the invention. These examples are non-exhaustive and are not intended to limit the scope of the invention.

Examples

Industrial Gear lubricating oil compositions were prepared as shown in the following Tables I (Comparative) and II (Inventive). Viscosity measurements for each base oil of lubricating viscosity were measured before and after the addition of additives using ASTM D445. Air release was measured for each lubricating oil composition according to ASTM D3427 at 50° C.

TABLE I Comparative Examples (wt %) Additive C1 C2 C3 C4 C5 C6 C7 C8 Ethylene 11 11 α-Olefin Copolymer Brightstock 50 50 50 Viscosity 12 12 14 Modifier³ Borated 0.04 0.04 0.11 0.11 0.11 0.04 dispersant Anti-Foam 0.02 0.02 0.02 Anti-Wear¹ 0.1 0.1 0.1 Anti-Wear² 0.61 0.61 0.61 Corrosion 0.5 0.5 0.15 0.15 0.15 0.5 Inhibitor Yellow metal 0.02 0.02 0.02 0.02 0.02 0.02 Inhibitor Demulsifier 0.006 0.006 0.006 0.006 0.006 0.01 Sulfurized 1.2 1.2 1.2 1.2 1.2 1.2 Olefin Oil of Balance Balance Balance Balance Balance Balance Balance Balance Lubricating to to to to to to to to Viscosity 100% 100% 100% 100% 100% 100% 100% 100% ISO VG 220 220 220 220 220 220 220 220 API BO Grp I I I I I II I II Air Release 36.8 39.3 43.4 36.4 34.2 25.9 41.9 27.1 ¹Anti-Wear Additive comprises an amine salt of a hydrocarbyl thiophosphoric acid ester obtained by reacting a phosphorous sulfide with one or more alcohols having about 3 to about 13 carbon atoms to form a thiophosphoric acid ester, further reacting the thiophosphoric acid ester with an alkylene oxide to form a hydroxyl-substituted ester of thiophosphoric acid, and further reacting said hydroxyl-substituted ester of thiophosphoric acid with a phosphorous oxide to form a an acidic phosphoric acid intermediate, and salting said acidic phosphoric acid intermediate with one or more amines wherein said amines contain one or more hydrocarbyl groups having from 2 to 30 carbon atoms as described herein. ²Anti-Wear Additive comprises an alkenyl phosphite based anti-wear additive. ³Viscosity Modifier comprises a polyisobutylene based viscosity modifier with an embedded pour point depressant.

TABLE II Comparative Examples Additive Ex. A Ex. B Ex. C Ex. D Ex. E Ex. F Ex. G Ex. H Ex. I Ex. J Ex. K Ethylene 5 5 2 13 13 11 11 11 11 11 11 α-Olefin Copolymer Dispersant 0.04 0.04 Borated 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 Dispersant Anti-Foam 0.02 0.02 0.02 0.02 0.02 0.02 Anti-Wear¹ 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.15 0.15 Corrosion 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.05 0.05 Inhibitor Yellow metal 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 Inhibitor Demulsifier 0.006 0.006 0.006 0.006 0.006 0.01 0.01 0.006 0.01 0.005 0.005 Antioxidant 0.19 0.19 Sulfurized 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 0.65 0.65 Olefin Oil of Balance Balance Balance Balance Balance Balance Balance Balance Balance Balance Balance Lubricating to to to to to to to to to to to Viscosity 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% ISO VG 150 150 68 220 220 220 220 220 220 220 220 API BO Grp II I II II II II II II II I II Air Release 17.5 23.8 5.8 20.5 17.1 13.4 10.5 16.1 17.2 16.9 13.9

It is known that some of the materials described above may interact in the final formulation, so that the components of the final formulation may be different from those that are initially added. The products formed thereby, including the products formed upon employing lubricant composition of the present invention in its intended use, may not be susceptible of easy description. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses lubricant composition prepared by admixing the components described above.

Each of the documents referred to above is incorporated herein by reference. Except in the Examples, or where otherwise explicitly indicated, all numerical quantities in this description specifying amounts of materials, reaction conditions, molecular weights, number of carbon atoms, and the like, are to be understood as modified by the word “about”. Unless otherwise indicated, each chemical or composition referred to herein should be interpreted as being a commercial grade material which may contain the isomers, by-products, derivatives, and other such materials which are normally understood to be present in the commercial grade. However, the amount of each chemical component is presented exclusive of any solvent or diluent oil, which may be customarily present in the commercial material, unless otherwise indicated. It is to be understood that the upper and lower amount, range, and ratio limits set forth herein may be independently combined. Similarly, the ranges and amounts for each element of the invention may be used together with ranges or amounts for any of the other elements.

While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims. 

What is claimed is:
 1. A lubricating oil composition comprising: (a) an oil of lubricating viscosity; (b) an ethylene/α-olefin copolymer; and (c) an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester.
 2. The lubricating oil composition of claim 1, wherein the additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester is obtained by reacting a phosphorous sulfide with one or more alcohols having about 3 to about 13 carbon atoms to form a thiophosphoric acid ester, further reacting the thiophosphoric acid ester with an alkylene oxide to form a hydroxyl-substituted ester of thiophosphoric acid, and further reacting said hydroxyl-substituted ester of thiophosphoric acid with a phosphorous oxide to form a an acidic phosphoric acid intermediate, and salting said acidic phosphoric acid intermediate with one or more amines wherein said amines contain one or more hydrocarbyl groups having from 2 to 30 carbon atoms.
 3. The lubricating oil composition of claim 1, wherein the ethylene/α-olefin copolymer comprises ethylene monomer units and one or more α-olefin monomer units other than ethylene monomer, wherein the amount of ethylene monomer units is greater than 5 weight percent, wherein the α-olefin monomer units contain 3 to about 20, or 3 to about 6, or 3 to 4, or 3 carbon atoms or mixtures thereof.
 4. The lubricating oil composition of claim 1, wherein the α-olefin monomer units of the ethylene/α-olefin copolymer comprise propylene units and monomer units containing 4 to about 20 carbon atoms.
 5. The lubricating oil composition of claim 1, wherein the ethylene/α-olefin copolymer has a kinematic viscosity at 100° C. of at least about 35 mm²/s or at least 500 mm²/s.
 6. The lubricating oil composition of claim 1, wherein the lubricating oil composition comprises about 11% to about 17% by weight of the ethylene/α-olefin copolymer.
 7. The lubricating oil composition of claim 1, wherein the lubricating oil composition comprises about 0.04% to about 0.15% by weight of the additive an amine salt of a hydrocarbyl thiophosphoric acid ester.
 8. The lubricating oil composition of claim 1, further comprising: an industrial additive package.
 9. A method of lubricating an industrial gear comprising supplying to the industrial gear the lubricating oil composition of claim
 1. 10. A method of improving the air release of a lubricating oil composition, comprising: (i) providing (a) a base oil of lubricating viscosity, (b) an ethylene/α-olefin copolymer, and (c) an additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester; (ii) mixing the base oil of lubricating viscosity, the ethylene/α-olefin copolymer, and the additive to obtain a functional fluid.
 11. The method of claim 10, wherein the additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester is obtained by reacting a phosphorous sulfide with one or more alcohols having about 3 to about 13 carbon atoms to form a thiophosphoric acid ester, further reacting the thiophosphoric acid ester with an alkylene oxide to form a hydroxyl-substituted ester of thiophosphoric acid, and further reacting said hydroxyl-substituted ester of thiophosphoric acid with a phosphorous oxide to form a an acidic phosphoric acid intermediate, and salting said acidic phosphoric acid intermediate with one or more amines wherein said amines contain one or more hydrocarbyl groups having from 2 to 30 carbon atoms.
 12. The method of claim 10, wherein the ethylene/α-olefin copolymer comprises ethylene monomer units and one or more α-olefin monomer units other than ethylene monomer, wherein the amount of ethylene monomer units is greater than 5 weight percent, wherein the α-olefin monomer units contain 3 to about 20, or 3 to about 6, or 3 to 4, or 3 carbon atoms or mixtures thereof.
 13. The method of claim 10, wherein the α-olefin monomer units of the ethylene/α-olefin copolymer comprise propylene units and monomer units containing 4 to about 20 carbon atoms.
 14. The method of claim 10, wherein the ethylene/α-olefin copolymer has a kinematic viscosity at 100° C. of at least about 35 mm²/s or at least 500 mm²/s.
 15. The method of claim 10, wherein the functional fluid contains about 11% to about 17% by weight of the ethylene/α-olefin copolymer.
 16. The method of claim 10, wherein the lubricating oil composition comprises about 0.04% to about 0.15% by weight of the additive an amine salt of a hydrocarbyl thiophosphoric acid ester.
 17. (canceled)
 18. (canceled) 